Neurodegenerative tauopathies, including Alzheimer's disease (AD), are characterized by the misfolding and aggregation of the microtubule (MT)-associated protein tau. Normally, tau binds to and stabilizes MTs, thereby maintaining the network of MTs essential for axonal transport in neurons. In AD, tau becomes sequestered into aggregates, known as neurofibrillary tangles (NFTs) and neuropil threads, resulting in reduced MT-binding. This loss of tau function is believed to lead to MT destabilization and consequent axonal transport deficits, which could result in neuronal dysfunction and death.
Other neurodegenerative diseases where MT function may be compromised include frontotemporal lobar degeneration, multiple sclerosis, Parkinson's disease, amyotrophic laterial sclerosis, schizophrenia, Huntington's disease, multiple sclerosis, and traumatic brain injury (TBI), especially repetitive TBI (rTBI) such as that due to dementia pugilistica and recurrent football concussions and military closed head injuries, which also is known as chronic traumatic encephalopathy (CTE).
Compounds that can cross the blood brain barrier and effectively stabilize MT are needed in order to treat neurodegenerative diseases caused, at least in part, by misfolding and aggregation of the MT-associated protein tau.